CN-A-1217675 discloses a blade clamping device which disadvantageously needs to be riveted together. U.S. Pat. No. 5,165,173 discloses a saw in which the blade is fixed to the drive shaft by means of fixing screws so that it is very inconvenient to remove the saw blade. In the blade clamping device of U.S. Pat. No. 5,324,052, the blade is pressed by a spring-loaded clamping piece against a slot wall but the clamping device is very big and its operation is inconvenient.